/*------------------------------------------------------------------------- * * tablespace.c * Commands to manipulate table spaces * * Tablespaces in PostgreSQL are designed to allow users to determine * where the data file(s) for a given database object reside on the file * system. * * A tablespace represents a directory on the file system. At tablespace * creation time, the directory must be empty. To simplify things and * remove the possibility of having file name conflicts, we isolate * files within a tablespace into database-specific subdirectories. * * To support file access via the information given in RelFileNode, we * maintain a symbolic-link map in $PGDATA/pg_tblspc. The symlinks are * named by tablespace OIDs and point to the actual tablespace directories. * Thus the full path to an arbitrary file is * $PGDATA/pg_tblspc/spcoid/dboid/relfilenode * * There are two tablespaces created at initdb time: pg_global (for shared * tables) and pg_default (for everything else). For backwards compatibility * and to remain functional on platforms without symlinks, these tablespaces * are accessed specially: they are respectively * $PGDATA/global/relfilenode * $PGDATA/base/dboid/relfilenode * * To allow CREATE DATABASE to give a new database a default tablespace * that's different from the template database's default, we make the * provision that a zero in pg_class.reltablespace means the database's * default tablespace. Without this, CREATE DATABASE would have to go in * and munge the system catalogs of the new database. * * * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.65 2010/01/02 16:57:37 momjian Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include #include #include #include #include "access/heapam.h" #include "access/sysattr.h" #include "access/transam.h" #include "access/xact.h" #include "catalog/catalog.h" #include "catalog/dependency.h" #include "catalog/indexing.h" #include "catalog/pg_tablespace.h" #include "commands/comment.h" #include "commands/tablespace.h" #include "miscadmin.h" #include "postmaster/bgwriter.h" #include "storage/fd.h" #include "storage/procarray.h" #include "storage/standby.h" #include "utils/acl.h" #include "utils/builtins.h" #include "utils/fmgroids.h" #include "utils/guc.h" #include "utils/lsyscache.h" #include "utils/memutils.h" #include "utils/rel.h" #include "utils/tqual.h" /* GUC variables */ char *default_tablespace = NULL; char *temp_tablespaces = NULL; static bool remove_tablespace_directories(Oid tablespaceoid, bool redo); static void set_short_version(const char *path); /* * Each database using a table space is isolated into its own name space * by a subdirectory named for the database OID. On first creation of an * object in the tablespace, create the subdirectory. If the subdirectory * already exists, just fall through quietly. * * isRedo indicates that we are creating an object during WAL replay. * In this case we will cope with the possibility of the tablespace * directory not being there either --- this could happen if we are * replaying an operation on a table in a subsequently-dropped tablespace. * We handle this by making a directory in the place where the tablespace * symlink would normally be. This isn't an exact replay of course, but * it's the best we can do given the available information. * * If tablespaces are not supported, you might think this could be a no-op, * but you'd be wrong: we still need it in case we have to re-create a * database subdirectory (of $PGDATA/base) during WAL replay. */ void TablespaceCreateDbspace(Oid spcNode, Oid dbNode, bool isRedo) { struct stat st; char *dir; /* * The global tablespace doesn't have per-database subdirectories, so * nothing to do for it. */ if (spcNode == GLOBALTABLESPACE_OID) return; Assert(OidIsValid(spcNode)); Assert(OidIsValid(dbNode)); dir = GetDatabasePath(dbNode, spcNode); if (stat(dir, &st) < 0) { if (errno == ENOENT) { /* * Acquire TablespaceCreateLock to ensure that no DROP TABLESPACE * or TablespaceCreateDbspace is running concurrently. */ LWLockAcquire(TablespaceCreateLock, LW_EXCLUSIVE); /* * Recheck to see if someone created the directory while we were * waiting for lock. */ if (stat(dir, &st) == 0 && S_ISDIR(st.st_mode)) { /* need not do anything */ } else { /* OK, go for it */ if (mkdir(dir, S_IRWXU) < 0) { char *parentdir; if (errno != ENOENT || !isRedo) ereport(ERROR, (errcode_for_file_access(), errmsg("could not create directory \"%s\": %m", dir))); /* Try to make parent directory too */ parentdir = pstrdup(dir); get_parent_directory(parentdir); if (mkdir(parentdir, S_IRWXU) < 0) ereport(ERROR, (errcode_for_file_access(), errmsg("could not create directory \"%s\": %m", parentdir))); pfree(parentdir); if (mkdir(dir, S_IRWXU) < 0) ereport(ERROR, (errcode_for_file_access(), errmsg("could not create directory \"%s\": %m", dir))); } } LWLockRelease(TablespaceCreateLock); } else { ereport(ERROR, (errcode_for_file_access(), errmsg("could not stat directory \"%s\": %m", dir))); } } else { /* be paranoid */ if (!S_ISDIR(st.st_mode)) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("\"%s\" exists but is not a directory", dir))); } pfree(dir); } /* * Create a table space * * Only superusers can create a tablespace. This seems a reasonable restriction * since we're determining the system layout and, anyway, we probably have * root if we're doing this kind of activity */ void CreateTableSpace(CreateTableSpaceStmt *stmt) { #ifdef HAVE_SYMLINK Relation rel; Datum values[Natts_pg_tablespace]; bool nulls[Natts_pg_tablespace]; HeapTuple tuple; Oid tablespaceoid; char *location; char *linkloc; Oid ownerId; /* Must be super user */ if (!superuser()) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("permission denied to create tablespace \"%s\"", stmt->tablespacename), errhint("Must be superuser to create a tablespace."))); /* However, the eventual owner of the tablespace need not be */ if (stmt->owner) ownerId = get_roleid_checked(stmt->owner); else ownerId = GetUserId(); /* Unix-ify the offered path, and strip any trailing slashes */ location = pstrdup(stmt->location); canonicalize_path(location); /* disallow quotes, else CREATE DATABASE would be at risk */ if (strchr(location, '\'')) ereport(ERROR, (errcode(ERRCODE_INVALID_NAME), errmsg("tablespace location cannot contain single quotes"))); /* * Allowing relative paths seems risky * * this also helps us ensure that location is not empty or whitespace */ if (!is_absolute_path(location)) ereport(ERROR, (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), errmsg("tablespace location must be an absolute path"))); /* * Check that location isn't too long. Remember that we're going to append * '//.' (XXX but do we ever form the whole path * explicitly? This may be overly conservative.) */ if (strlen(location) >= (MAXPGPATH - 1 - 10 - 1 - 10 - 1 - 10)) ereport(ERROR, (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), errmsg("tablespace location \"%s\" is too long", location))); /* * Disallow creation of tablespaces named "pg_xxx"; we reserve this * namespace for system purposes. */ if (!allowSystemTableMods && IsReservedName(stmt->tablespacename)) ereport(ERROR, (errcode(ERRCODE_RESERVED_NAME), errmsg("unacceptable tablespace name \"%s\"", stmt->tablespacename), errdetail("The prefix \"pg_\" is reserved for system tablespaces."))); /* * Check that there is no other tablespace by this name. (The unique * index would catch this anyway, but might as well give a friendlier * message.) */ if (OidIsValid(get_tablespace_oid(stmt->tablespacename))) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("tablespace \"%s\" already exists", stmt->tablespacename))); /* * Insert tuple into pg_tablespace. The purpose of doing this first is to * lock the proposed tablename against other would-be creators. The * insertion will roll back if we find problems below. */ rel = heap_open(TableSpaceRelationId, RowExclusiveLock); MemSet(nulls, false, sizeof(nulls)); values[Anum_pg_tablespace_spcname - 1] = DirectFunctionCall1(namein, CStringGetDatum(stmt->tablespacename)); values[Anum_pg_tablespace_spcowner - 1] = ObjectIdGetDatum(ownerId); values[Anum_pg_tablespace_spclocation - 1] = CStringGetTextDatum(location); nulls[Anum_pg_tablespace_spcacl - 1] = true; tuple = heap_form_tuple(rel->rd_att, values, nulls); tablespaceoid = simple_heap_insert(rel, tuple); CatalogUpdateIndexes(rel, tuple); heap_freetuple(tuple); /* Record dependency on owner */ recordDependencyOnOwner(TableSpaceRelationId, tablespaceoid, ownerId); /* * Attempt to coerce target directory to safe permissions. If this fails, * it doesn't exist or has the wrong owner. */ if (chmod(location, 0700) != 0) ereport(ERROR, (errcode_for_file_access(), errmsg("could not set permissions on directory \"%s\": %m", location))); /* * Check the target directory is empty. */ if (!directory_is_empty(location)) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("directory \"%s\" is not empty", location))); /* * Create the PG_VERSION file in the target directory. This has several * purposes: to make sure we can write in the directory, to prevent * someone from creating another tablespace pointing at the same directory * (the emptiness check above will fail), and to label tablespace * directories by PG version. */ set_short_version(location); /* * All seems well, create the symlink */ linkloc = (char *) palloc(10 + 10 + 1); sprintf(linkloc, "pg_tblspc/%u", tablespaceoid); if (symlink(location, linkloc) < 0) ereport(ERROR, (errcode_for_file_access(), errmsg("could not create symbolic link \"%s\": %m", linkloc))); /* Record the filesystem change in XLOG */ { xl_tblspc_create_rec xlrec; XLogRecData rdata[2]; xlrec.ts_id = tablespaceoid; rdata[0].data = (char *) &xlrec; rdata[0].len = offsetof(xl_tblspc_create_rec, ts_path); rdata[0].buffer = InvalidBuffer; rdata[0].next = &(rdata[1]); rdata[1].data = (char *) location; rdata[1].len = strlen(location) + 1; rdata[1].buffer = InvalidBuffer; rdata[1].next = NULL; (void) XLogInsert(RM_TBLSPC_ID, XLOG_TBLSPC_CREATE, rdata); } /* * Force synchronous commit, to minimize the window between creating the * symlink on-disk and marking the transaction committed. It's not great * that there is any window at all, but definitely we don't want to make * it larger than necessary. */ ForceSyncCommit(); pfree(linkloc); pfree(location); /* We keep the lock on pg_tablespace until commit */ heap_close(rel, NoLock); #else /* !HAVE_SYMLINK */ ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("tablespaces are not supported on this platform"))); #endif /* HAVE_SYMLINK */ } /* * Drop a table space * * Be careful to check that the tablespace is empty. */ void DropTableSpace(DropTableSpaceStmt *stmt) { #ifdef HAVE_SYMLINK char *tablespacename = stmt->tablespacename; HeapScanDesc scandesc; Relation rel; HeapTuple tuple; ScanKeyData entry[1]; Oid tablespaceoid; /* * Find the target tuple */ rel = heap_open(TableSpaceRelationId, RowExclusiveLock); ScanKeyInit(&entry[0], Anum_pg_tablespace_spcname, BTEqualStrategyNumber, F_NAMEEQ, CStringGetDatum(tablespacename)); scandesc = heap_beginscan(rel, SnapshotNow, 1, entry); tuple = heap_getnext(scandesc, ForwardScanDirection); if (!HeapTupleIsValid(tuple)) { if (!stmt->missing_ok) { ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("tablespace \"%s\" does not exist", tablespacename))); } else { ereport(NOTICE, (errmsg("tablespace \"%s\" does not exist, skipping", tablespacename))); /* XXX I assume I need one or both of these next two calls */ heap_endscan(scandesc); heap_close(rel, NoLock); } return; } tablespaceoid = HeapTupleGetOid(tuple); /* Must be tablespace owner */ if (!pg_tablespace_ownercheck(tablespaceoid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TABLESPACE, tablespacename); /* Disallow drop of the standard tablespaces, even by superuser */ if (tablespaceoid == GLOBALTABLESPACE_OID || tablespaceoid == DEFAULTTABLESPACE_OID) aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_TABLESPACE, tablespacename); /* * Remove the pg_tablespace tuple (this will roll back if we fail below) */ simple_heap_delete(rel, &tuple->t_self); heap_endscan(scandesc); /* * Remove any comments on this tablespace. */ DeleteSharedComments(tablespaceoid, TableSpaceRelationId); /* * Remove dependency on owner. */ deleteSharedDependencyRecordsFor(TableSpaceRelationId, tablespaceoid, 0); /* * Acquire TablespaceCreateLock to ensure that no TablespaceCreateDbspace * is running concurrently. */ LWLockAcquire(TablespaceCreateLock, LW_EXCLUSIVE); /* * Try to remove the physical infrastructure. */ if (!remove_tablespace_directories(tablespaceoid, false)) { /* * Not all files deleted? However, there can be lingering empty files * in the directories, left behind by for example DROP TABLE, that * have been scheduled for deletion at next checkpoint (see comments * in mdunlink() for details). We could just delete them immediately, * but we can't tell them apart from important data files that we * mustn't delete. So instead, we force a checkpoint which will clean * out any lingering files, and try again. */ RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT); if (!remove_tablespace_directories(tablespaceoid, false)) { /* Still not empty, the files must be important then */ ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("tablespace \"%s\" is not empty", tablespacename))); } } /* Record the filesystem change in XLOG */ { xl_tblspc_drop_rec xlrec; XLogRecData rdata[1]; xlrec.ts_id = tablespaceoid; rdata[0].data = (char *) &xlrec; rdata[0].len = sizeof(xl_tblspc_drop_rec); rdata[0].buffer = InvalidBuffer; rdata[0].next = NULL; (void) XLogInsert(RM_TBLSPC_ID, XLOG_TBLSPC_DROP, rdata); } /* * Note: because we checked that the tablespace was empty, there should be * no need to worry about flushing shared buffers or free space map * entries for relations in the tablespace. */ /* * Force synchronous commit, to minimize the window between removing the * files on-disk and marking the transaction committed. It's not great * that there is any window at all, but definitely we don't want to make * it larger than necessary. */ ForceSyncCommit(); /* * Allow TablespaceCreateDbspace again. */ LWLockRelease(TablespaceCreateLock); /* We keep the lock on pg_tablespace until commit */ heap_close(rel, NoLock); #else /* !HAVE_SYMLINK */ ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("tablespaces are not supported on this platform"))); #endif /* HAVE_SYMLINK */ } /* * remove_tablespace_directories: attempt to remove filesystem infrastructure * * Returns TRUE if successful, FALSE if some subdirectory is not empty * * redo indicates we are redoing a drop from XLOG; okay if nothing there */ static bool remove_tablespace_directories(Oid tablespaceoid, bool redo) { char *location; DIR *dirdesc; struct dirent *de; char *subfile; struct stat st; location = (char *) palloc(10 + 10 + 1); sprintf(location, "pg_tblspc/%u", tablespaceoid); /* * Check if the tablespace still contains any files. We try to rmdir each * per-database directory we find in it. rmdir failure implies there are * still files in that subdirectory, so give up. (We do not have to worry * about undoing any already completed rmdirs, since the next attempt to * use the tablespace from that database will simply recreate the * subdirectory via TablespaceCreateDbspace.) * * Since we hold TablespaceCreateLock, no one else should be creating any * fresh subdirectories in parallel. It is possible that new files are * being created within subdirectories, though, so the rmdir call could * fail. Worst consequence is a less friendly error message. * * If redo is true then ENOENT is a likely outcome here, and we allow it * to pass without comment. In normal operation we still allow it, but * with a warning. This is because even though ProcessUtility disallows * DROP TABLESPACE in a transaction block, it's possible that a previous * DROP failed and rolled back after removing the tablespace directories * and symlink. We want to allow a new DROP attempt to succeed at * removing the catalog entries, so we should not give a hard error here. */ dirdesc = AllocateDir(location); if (dirdesc == NULL) { if (errno == ENOENT) { if (!redo) ereport(WARNING, (errcode_for_file_access(), errmsg("could not open directory \"%s\": %m", location))); pfree(location); return true; } /* else let ReadDir report the error */ } while ((de = ReadDir(dirdesc, location)) != NULL) { /* Note we ignore PG_VERSION for the nonce */ if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0 || strcmp(de->d_name, "PG_VERSION") == 0) continue; subfile = palloc(strlen(location) + 1 + strlen(de->d_name) + 1); sprintf(subfile, "%s/%s", location, de->d_name); /* This check is just to deliver a friendlier error message */ if (!directory_is_empty(subfile)) { FreeDir(dirdesc); return false; } /* Do the real deed */ if (rmdir(subfile) < 0) ereport(ERROR, (errcode_for_file_access(), errmsg("could not remove directory \"%s\": %m", subfile))); pfree(subfile); } FreeDir(dirdesc); /* * Okay, try to unlink PG_VERSION (we allow it to not be there, even in * non-REDO case, for robustness). */ subfile = palloc(strlen(location) + 11 + 1); sprintf(subfile, "%s/PG_VERSION", location); if (unlink(subfile) < 0) { if (errno != ENOENT) ereport(ERROR, (errcode_for_file_access(), errmsg("could not remove file \"%s\": %m", subfile))); } pfree(subfile); /* * Okay, try to remove the symlink. We must however deal with the * possibility that it's a directory instead of a symlink --- this could * happen during WAL replay (see TablespaceCreateDbspace), and it is also * the normal case on Windows. */ if (lstat(location, &st) == 0 && S_ISDIR(st.st_mode)) { if (rmdir(location) < 0) ereport(ERROR, (errcode_for_file_access(), errmsg("could not remove directory \"%s\": %m", location))); } else { if (unlink(location) < 0) ereport(ERROR, (errcode_for_file_access(), errmsg("could not remove symbolic link \"%s\": %m", location))); } pfree(location); return true; } /* * write out the PG_VERSION file in the specified directory */ static void set_short_version(const char *path) { char *short_version; bool gotdot = false; int end; char *fullname; FILE *version_file; /* Construct short version string (should match initdb.c) */ short_version = pstrdup(PG_VERSION); for (end = 0; short_version[end] != '\0'; end++) { if (short_version[end] == '.') { Assert(end != 0); if (gotdot) break; else gotdot = true; } else if (short_version[end] < '0' || short_version[end] > '9') { /* gone past digits and dots */ break; } } Assert(end > 0 && short_version[end - 1] != '.' && gotdot); short_version[end] = '\0'; /* Now write the file */ fullname = palloc(strlen(path) + 11 + 1); sprintf(fullname, "%s/PG_VERSION", path); version_file = AllocateFile(fullname, PG_BINARY_W); if (version_file == NULL) ereport(ERROR, (errcode_for_file_access(), errmsg("could not write to file \"%s\": %m", fullname))); fprintf(version_file, "%s\n", short_version); if (FreeFile(version_file)) ereport(ERROR, (errcode_for_file_access(), errmsg("could not write to file \"%s\": %m", fullname))); pfree(fullname); pfree(short_version); } /* * Check if a directory is empty. * * This probably belongs somewhere else, but not sure where... */ bool directory_is_empty(const char *path) { DIR *dirdesc; struct dirent *de; dirdesc = AllocateDir(path); while ((de = ReadDir(dirdesc, path)) != NULL) { if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0) continue; FreeDir(dirdesc); return false; } FreeDir(dirdesc); return true; } /* * Rename a tablespace */ void RenameTableSpace(const char *oldname, const char *newname) { Relation rel; ScanKeyData entry[1]; HeapScanDesc scan; HeapTuple tup; HeapTuple newtuple; Form_pg_tablespace newform; /* Search pg_tablespace */ rel = heap_open(TableSpaceRelationId, RowExclusiveLock); ScanKeyInit(&entry[0], Anum_pg_tablespace_spcname, BTEqualStrategyNumber, F_NAMEEQ, CStringGetDatum(oldname)); scan = heap_beginscan(rel, SnapshotNow, 1, entry); tup = heap_getnext(scan, ForwardScanDirection); if (!HeapTupleIsValid(tup)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("tablespace \"%s\" does not exist", oldname))); newtuple = heap_copytuple(tup); newform = (Form_pg_tablespace) GETSTRUCT(newtuple); heap_endscan(scan); /* Must be owner */ if (!pg_tablespace_ownercheck(HeapTupleGetOid(newtuple), GetUserId())) aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_TABLESPACE, oldname); /* Validate new name */ if (!allowSystemTableMods && IsReservedName(newname)) ereport(ERROR, (errcode(ERRCODE_RESERVED_NAME), errmsg("unacceptable tablespace name \"%s\"", newname), errdetail("The prefix \"pg_\" is reserved for system tablespaces."))); /* Make sure the new name doesn't exist */ ScanKeyInit(&entry[0], Anum_pg_tablespace_spcname, BTEqualStrategyNumber, F_NAMEEQ, CStringGetDatum(newname)); scan = heap_beginscan(rel, SnapshotNow, 1, entry); tup = heap_getnext(scan, ForwardScanDirection); if (HeapTupleIsValid(tup)) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("tablespace \"%s\" already exists", newname))); heap_endscan(scan); /* OK, update the entry */ namestrcpy(&(newform->spcname), newname); simple_heap_update(rel, &newtuple->t_self, newtuple); CatalogUpdateIndexes(rel, newtuple); heap_close(rel, NoLock); } /* * Change tablespace owner */ void AlterTableSpaceOwner(const char *name, Oid newOwnerId) { Relation rel; ScanKeyData entry[1]; HeapScanDesc scandesc; Form_pg_tablespace spcForm; HeapTuple tup; /* Search pg_tablespace */ rel = heap_open(TableSpaceRelationId, RowExclusiveLock); ScanKeyInit(&entry[0], Anum_pg_tablespace_spcname, BTEqualStrategyNumber, F_NAMEEQ, CStringGetDatum(name)); scandesc = heap_beginscan(rel, SnapshotNow, 1, entry); tup = heap_getnext(scandesc, ForwardScanDirection); if (!HeapTupleIsValid(tup)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("tablespace \"%s\" does not exist", name))); spcForm = (Form_pg_tablespace) GETSTRUCT(tup); /* * If the new owner is the same as the existing owner, consider the * command to have succeeded. This is for dump restoration purposes. */ if (spcForm->spcowner != newOwnerId) { Datum repl_val[Natts_pg_tablespace]; bool repl_null[Natts_pg_tablespace]; bool repl_repl[Natts_pg_tablespace]; Acl *newAcl; Datum aclDatum; bool isNull; HeapTuple newtuple; /* Otherwise, must be owner of the existing object */ if (!pg_tablespace_ownercheck(HeapTupleGetOid(tup), GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TABLESPACE, name); /* Must be able to become new owner */ check_is_member_of_role(GetUserId(), newOwnerId); /* * Normally we would also check for create permissions here, but there * are none for tablespaces so we follow what rename tablespace does * and omit the create permissions check. * * NOTE: Only superusers may create tablespaces to begin with and so * initially only a superuser would be able to change its ownership * anyway. */ memset(repl_null, false, sizeof(repl_null)); memset(repl_repl, false, sizeof(repl_repl)); repl_repl[Anum_pg_tablespace_spcowner - 1] = true; repl_val[Anum_pg_tablespace_spcowner - 1] = ObjectIdGetDatum(newOwnerId); /* * Determine the modified ACL for the new owner. This is only * necessary when the ACL is non-null. */ aclDatum = heap_getattr(tup, Anum_pg_tablespace_spcacl, RelationGetDescr(rel), &isNull); if (!isNull) { newAcl = aclnewowner(DatumGetAclP(aclDatum), spcForm->spcowner, newOwnerId); repl_repl[Anum_pg_tablespace_spcacl - 1] = true; repl_val[Anum_pg_tablespace_spcacl - 1] = PointerGetDatum(newAcl); } newtuple = heap_modify_tuple(tup, RelationGetDescr(rel), repl_val, repl_null, repl_repl); simple_heap_update(rel, &newtuple->t_self, newtuple); CatalogUpdateIndexes(rel, newtuple); heap_freetuple(newtuple); /* Update owner dependency reference */ changeDependencyOnOwner(TableSpaceRelationId, HeapTupleGetOid(tup), newOwnerId); } heap_endscan(scandesc); heap_close(rel, NoLock); } /* * Routines for handling the GUC variable 'default_tablespace'. */ /* assign_hook: validate new default_tablespace, do extra actions as needed */ const char * assign_default_tablespace(const char *newval, bool doit, GucSource source) { /* * If we aren't inside a transaction, we cannot do database access so * cannot verify the name. Must accept the value on faith. */ if (IsTransactionState()) { if (newval[0] != '\0' && !OidIsValid(get_tablespace_oid(newval))) { ereport(GUC_complaint_elevel(source), (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("tablespace \"%s\" does not exist", newval))); return NULL; } } return newval; } /* * GetDefaultTablespace -- get the OID of the current default tablespace * * Regular objects and temporary objects have different default tablespaces, * hence the forTemp parameter must be specified. * * May return InvalidOid to indicate "use the database's default tablespace". * * Note that caller is expected to check appropriate permissions for any * result other than InvalidOid. * * This exists to hide (and possibly optimize the use of) the * default_tablespace GUC variable. */ Oid GetDefaultTablespace(bool forTemp) { Oid result; /* The temp-table case is handled elsewhere */ if (forTemp) { PrepareTempTablespaces(); return GetNextTempTableSpace(); } /* Fast path for default_tablespace == "" */ if (default_tablespace == NULL || default_tablespace[0] == '\0') return InvalidOid; /* * It is tempting to cache this lookup for more speed, but then we would * fail to detect the case where the tablespace was dropped since the GUC * variable was set. Note also that we don't complain if the value fails * to refer to an existing tablespace; we just silently return InvalidOid, * causing the new object to be created in the database's tablespace. */ result = get_tablespace_oid(default_tablespace); /* * Allow explicit specification of database's default tablespace in * default_tablespace without triggering permissions checks. */ if (result == MyDatabaseTableSpace) result = InvalidOid; return result; } /* * Routines for handling the GUC variable 'temp_tablespaces'. */ /* assign_hook: validate new temp_tablespaces, do extra actions as needed */ const char * assign_temp_tablespaces(const char *newval, bool doit, GucSource source) { char *rawname; List *namelist; /* Need a modifiable copy of string */ rawname = pstrdup(newval); /* Parse string into list of identifiers */ if (!SplitIdentifierString(rawname, ',', &namelist)) { /* syntax error in name list */ pfree(rawname); list_free(namelist); return NULL; } /* * If we aren't inside a transaction, we cannot do database access so * cannot verify the individual names. Must accept the list on faith. * Fortunately, there's then also no need to pass the data to fd.c. */ if (IsTransactionState()) { /* * If we error out below, or if we are called multiple times in one * transaction, we'll leak a bit of TopTransactionContext memory. * Doesn't seem worth worrying about. */ Oid *tblSpcs; int numSpcs; ListCell *l; tblSpcs = (Oid *) MemoryContextAlloc(TopTransactionContext, list_length(namelist) * sizeof(Oid)); numSpcs = 0; foreach(l, namelist) { char *curname = (char *) lfirst(l); Oid curoid; AclResult aclresult; /* Allow an empty string (signifying database default) */ if (curname[0] == '\0') { tblSpcs[numSpcs++] = InvalidOid; continue; } /* Else verify that name is a valid tablespace name */ curoid = get_tablespace_oid(curname); if (curoid == InvalidOid) { /* * In an interactive SET command, we ereport for bad info. * Otherwise, silently ignore any bad list elements. */ if (source >= PGC_S_INTERACTIVE) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("tablespace \"%s\" does not exist", curname))); continue; } /* * Allow explicit specification of database's default tablespace * in temp_tablespaces without triggering permissions checks. */ if (curoid == MyDatabaseTableSpace) { tblSpcs[numSpcs++] = InvalidOid; continue; } /* Check permissions similarly */ aclresult = pg_tablespace_aclcheck(curoid, GetUserId(), ACL_CREATE); if (aclresult != ACLCHECK_OK) { if (source >= PGC_S_INTERACTIVE) aclcheck_error(aclresult, ACL_KIND_TABLESPACE, curname); continue; } tblSpcs[numSpcs++] = curoid; } /* If actively "doing it", give the new list to fd.c */ if (doit) SetTempTablespaces(tblSpcs, numSpcs); else pfree(tblSpcs); } pfree(rawname); list_free(namelist); return newval; } /* * PrepareTempTablespaces -- prepare to use temp tablespaces * * If we have not already done so in the current transaction, parse the * temp_tablespaces GUC variable and tell fd.c which tablespace(s) to use * for temp files. */ void PrepareTempTablespaces(void) { char *rawname; List *namelist; Oid *tblSpcs; int numSpcs; ListCell *l; /* No work if already done in current transaction */ if (TempTablespacesAreSet()) return; /* * Can't do catalog access unless within a transaction. This is just a * safety check in case this function is called by low-level code that * could conceivably execute outside a transaction. Note that in such a * scenario, fd.c will fall back to using the current database's default * tablespace, which should always be OK. */ if (!IsTransactionState()) return; /* Need a modifiable copy of string */ rawname = pstrdup(temp_tablespaces); /* Parse string into list of identifiers */ if (!SplitIdentifierString(rawname, ',', &namelist)) { /* syntax error in name list */ SetTempTablespaces(NULL, 0); pfree(rawname); list_free(namelist); return; } /* Store tablespace OIDs in an array in TopTransactionContext */ tblSpcs = (Oid *) MemoryContextAlloc(TopTransactionContext, list_length(namelist) * sizeof(Oid)); numSpcs = 0; foreach(l, namelist) { char *curname = (char *) lfirst(l); Oid curoid; AclResult aclresult; /* Allow an empty string (signifying database default) */ if (curname[0] == '\0') { tblSpcs[numSpcs++] = InvalidOid; continue; } /* Else verify that name is a valid tablespace name */ curoid = get_tablespace_oid(curname); if (curoid == InvalidOid) { /* Silently ignore any bad list elements */ continue; } /* * Allow explicit specification of database's default tablespace in * temp_tablespaces without triggering permissions checks. */ if (curoid == MyDatabaseTableSpace) { tblSpcs[numSpcs++] = InvalidOid; continue; } /* Check permissions similarly */ aclresult = pg_tablespace_aclcheck(curoid, GetUserId(), ACL_CREATE); if (aclresult != ACLCHECK_OK) continue; tblSpcs[numSpcs++] = curoid; } SetTempTablespaces(tblSpcs, numSpcs); pfree(rawname); list_free(namelist); } /* * get_tablespace_oid - given a tablespace name, look up the OID * * Returns InvalidOid if tablespace name not found. */ Oid get_tablespace_oid(const char *tablespacename) { Oid result; Relation rel; HeapScanDesc scandesc; HeapTuple tuple; ScanKeyData entry[1]; /* * Search pg_tablespace. We use a heapscan here even though there is an * index on name, on the theory that pg_tablespace will usually have just * a few entries and so an indexed lookup is a waste of effort. */ rel = heap_open(TableSpaceRelationId, AccessShareLock); ScanKeyInit(&entry[0], Anum_pg_tablespace_spcname, BTEqualStrategyNumber, F_NAMEEQ, CStringGetDatum(tablespacename)); scandesc = heap_beginscan(rel, SnapshotNow, 1, entry); tuple = heap_getnext(scandesc, ForwardScanDirection); /* We assume that there can be at most one matching tuple */ if (HeapTupleIsValid(tuple)) result = HeapTupleGetOid(tuple); else result = InvalidOid; heap_endscan(scandesc); heap_close(rel, AccessShareLock); return result; } /* * get_tablespace_name - given a tablespace OID, look up the name * * Returns a palloc'd string, or NULL if no such tablespace. */ char * get_tablespace_name(Oid spc_oid) { char *result; Relation rel; HeapScanDesc scandesc; HeapTuple tuple; ScanKeyData entry[1]; /* * Search pg_tablespace. We use a heapscan here even though there is an * index on oid, on the theory that pg_tablespace will usually have just a * few entries and so an indexed lookup is a waste of effort. */ rel = heap_open(TableSpaceRelationId, AccessShareLock); ScanKeyInit(&entry[0], ObjectIdAttributeNumber, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(spc_oid)); scandesc = heap_beginscan(rel, SnapshotNow, 1, entry); tuple = heap_getnext(scandesc, ForwardScanDirection); /* We assume that there can be at most one matching tuple */ if (HeapTupleIsValid(tuple)) result = pstrdup(NameStr(((Form_pg_tablespace) GETSTRUCT(tuple))->spcname)); else result = NULL; heap_endscan(scandesc); heap_close(rel, AccessShareLock); return result; } /* * TABLESPACE resource manager's routines */ void tblspc_redo(XLogRecPtr lsn, XLogRecord *record) { uint8 info = record->xl_info & ~XLR_INFO_MASK; /* Backup blocks are not used in tblspc records */ Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK)); if (info == XLOG_TBLSPC_CREATE) { xl_tblspc_create_rec *xlrec = (xl_tblspc_create_rec *) XLogRecGetData(record); char *location = xlrec->ts_path; char *linkloc; /* * Attempt to coerce target directory to safe permissions. If this * fails, it doesn't exist or has the wrong owner. */ if (chmod(location, 0700) != 0) ereport(ERROR, (errcode_for_file_access(), errmsg("could not set permissions on directory \"%s\": %m", location))); /* Create or re-create the PG_VERSION file in the target directory */ set_short_version(location); /* Create the symlink if not already present */ linkloc = (char *) palloc(10 + 10 + 1); sprintf(linkloc, "pg_tblspc/%u", xlrec->ts_id); if (symlink(location, linkloc) < 0) { if (errno != EEXIST) ereport(ERROR, (errcode_for_file_access(), errmsg("could not create symbolic link \"%s\": %m", linkloc))); } pfree(linkloc); } else if (info == XLOG_TBLSPC_DROP) { xl_tblspc_drop_rec *xlrec = (xl_tblspc_drop_rec *) XLogRecGetData(record); /* * If we issued a WAL record for a drop tablespace it is * because there were no files in it at all. That means that * no permanent objects can exist in it at this point. * * It is possible for standby users to be using this tablespace * as a location for their temporary files, so if we fail to * remove all files then do conflict processing and try again, * if currently enabled. */ if (!remove_tablespace_directories(xlrec->ts_id, true)) { VirtualTransactionId *temp_file_users; /* * Standby users may be currently using this tablespace for * for their temporary files. We only care about current * users because temp_tablespace parameter will just ignore * tablespaces that no longer exist. * * Ask everybody to cancel their queries immediately so * we can ensure no temp files remain and we can remove the * tablespace. Nuke the entire site from orbit, it's the only * way to be sure. * * XXX: We could work out the pids of active backends * using this tablespace by examining the temp filenames in the * directory. We would then convert the pids into VirtualXIDs * before attempting to cancel them. * * We don't wait for commit because drop tablespace is * non-transactional. */ temp_file_users = GetConflictingVirtualXIDs(InvalidTransactionId, InvalidOid, false); ResolveRecoveryConflictWithVirtualXIDs(temp_file_users, "drop tablespace", CONFLICT_MODE_ERROR); /* * If we did recovery processing then hopefully the * backends who wrote temp files should have cleaned up and * exited by now. So lets recheck before we throw an error. * If !process_conflicts then this will just fail again. */ if (!remove_tablespace_directories(xlrec->ts_id, true)) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("tablespace %u is not empty", xlrec->ts_id))); } } else elog(PANIC, "tblspc_redo: unknown op code %u", info); } void tblspc_desc(StringInfo buf, uint8 xl_info, char *rec) { uint8 info = xl_info & ~XLR_INFO_MASK; if (info == XLOG_TBLSPC_CREATE) { xl_tblspc_create_rec *xlrec = (xl_tblspc_create_rec *) rec; appendStringInfo(buf, "create ts: %u \"%s\"", xlrec->ts_id, xlrec->ts_path); } else if (info == XLOG_TBLSPC_DROP) { xl_tblspc_drop_rec *xlrec = (xl_tblspc_drop_rec *) rec; appendStringInfo(buf, "drop ts: %u", xlrec->ts_id); } else appendStringInfo(buf, "UNKNOWN"); }